Optical and optoelectronic systems generally provide complex waveguide structures which are used for the transport of an optical signal. In numerous applications, a signal delay time controllable to an accuracy of a few fs is required in order to achieve a required performance of the overall system. For example, U.S. Pat. No. 7,956,788 B2 discloses an optoelectronic analog-digital converter in which individual sample-and-hold elements are controlled with an optical clock signal.
Scattering of the sampling times occurs within the optical network and also in the electronic components in a manner dependent upon manufacture. These scatterings are caused, for example, by tolerances in the geometric manufacture of the waveguides, tolerances in the refractive indices of the waveguides, but also through tolerances in the electronic components. Added to this, thermal gradients in the circuit lead to position-dependent fluctuations in the delay times of the optical and electronic components.
One value relevant for the performance of the overall system is the time precision with which the analog signal is sampled. In particular, with the use of N time-nested samplers, which together provide a sampler with N-fold sampling rate, an exact sampling is necessary at the time t0+(M/N)*t_clock. In this context, M denotes the number of the individual samplers in the system. If it is not possible to guarantee a time-exact sampling between the samplers, undesirable secondary lines occur in the signal reconstructed from the individual samplers.
This leads to the need of providing an optoelectronic circuit and a method for operating an optoelectronic circuit which allow a very precise observation of the planned delay times of the signal.